1. Technical Field
The present invention relates, in general, to a method and system which yield improvements to virtual terminal applications. In particular, the present invention relates to a method and system which yield improvements to virtual terminal applications and which empower the virtual terminal applications to actually serve as identically functioning replacements for physical terminals within existing computer systems.
2. Description of Related Art
With the current all-pervasive nature of widespread use of internetworking to interact with the World Wide Web, and to accomplish networked/distributed computing, it is easy to forget just how relatively new such widespread use is. Since the need for the present invention, at least in part, relates to and arises from the historical newness of such widespread use, it is helpful to set such use in a historical context, which can then serve as a springboard for introducing certain aspects of the needs for and utilities of the present invention.
Virtually no one foresaw the current pervasive nature of the widespread use of internetworking (for reasons that will be discussed below). Indeed, prior to the early 1990s, the belief among information officers at leading business concerns was that the future of computing lay in the use of mid-range to upper end computing systems (i.e. mid-range to mainframe computing systems). Consequently, throughout the sustained economic expansion of the middle and late 1980s, many business concerns invested heavily in mid-range and mainframe computing systems to serve their business interests.
In addition to investing in the hardware to serve their interests, many, if not most, business concerns also made concomitant investments in software to run on such mid-range and mainframe computing systems. Such software was often custom designed for the interests of each individual business concern and hence very expensive. Taken together such hardware and software tended to represent a significant investment for business concerns.
By the end of the 1980s, much of the expansion in computing resources among business concerns was nearing its end. It was not uncommon at the time for trade magazines to trumpet the glut of Ph.D. computer scientists and the inability of such highly trained individuals to obtain employment. It was widely acknowledged that the demise of the computing industry was imminent. However, as is well known, such demise never came to be. Rather, the computer industry was revitalized and thrown into a full-blown expansion due to the explosion of internetworking.
The explosion of internetworking can best be illustrated in reference to the explosion of use of the public Internet. The explosion of use of the public Internet can be traced to invention of the World Wide Web application software, and the subsequent attendant rise of very powerful programs, known as web browsers, which freed even non-technical people to use the power of, and communicate over, the Internet.
In 1989 the World Wide Web (WWW) was developed by English computer scientist Timothy Berners-Lee. Although the name World Wide Web would seem to indicate that the WWW is a network, it is not. The WWW is actually an application program which runs on individual computers and that creates connections to multiple different source computers over one or more networks. All WWW computer files are formatted using Hypertext Markup Language (HTML), and WWW communication among computers occurs using the Hypertext Transfer Protocol (HTTP). A computer file formatted in HTML is called a "web page" in WWW parlance.
For reasons that are not exactly clear, the invention of the World Wide Web gave rise to the invention of application programs generally known as WWW browsers (e.g., Netscape Navigator). A WWW browser program allows a file formatted in HTML/HTTP format (i.e. "web pages") to be displayed on a computer screen as an agglomeration of text, images, sound, or other visual objects, which can appear as highlighted texts or graphics, and which are in actuality subprograms to establish communications links with other machines internetworked and running WWW software. Furthermore, modern browsers have additional embedded applications (such as File Transfer Protocol, for transferring files, or Gopher, for remotely viewing files on another system, or Telnet for remotely accessing computer systems) which are automatically activated when such applications are needed. Thus, the invention of the World Wide Web and attendant rise of web browsers made Internet communication as easy as pointing and clicking on a graphical object.
Thus, while the Internet proper is not that new, the WWW application and most importantly the browser applications that it spawned, which automated much of the protocol specification that once had been the sole province of the computer adept, placed access to the information within the Internet into the hands of the virtually everyone. When this was achieved, the aforementioned explosion in information processing and network computing occurred. However, remember that such explosion, dates, at its earliest, only from 1989 (and even later, if the true, practical effects generated by powerful browsers are what are of interest).
Due to the competitive advantage that the Internet, WWW, and network computing confer, a majority of business concerns have been forced to purchase newer computing equipment which are Internet, WWW, and network computing compatible. However, as has been discussed above, those same concerns also often have older and larger computing systems that are still in use, but were purchased before the "Internet revolution." Furthermore, since these extant older systems often represent a significant investment in hardware and specialized software, and often provide a great deal of computing power, such concerns are often desirous to continue to use such hardware and software.
A good example of the foregoing would be the IBM AS/400 mid-range computing system. Although the AS/400 is still in production and use, the AS/400 was introduced prior to 1989, and hence pre-dated the WWW and Internet revolution.
Users have traditionally accessed the AS/400 via actual, physical, terminals which are physically connected to and designed for the AS/400. Indeed, this was the standard method of doing business on mid-range and mainframe computers prior to the explosion of use of the Internet.
Business concerns have begun to request that newer Internet/WWW compatible machines be given the capability to replace the actual physical terminals connected to the AS/400 machines. That is, business concerns have expressed their desire that a user be able to utilize a personal computer to connect to and interface with the AS/400 machines and programs much in the same manner that a web browser is able to connect and communicate with many different computers and programs. Furthermore, it appears to such business concerns that such connections should be able to be made given that modern web browsers interact with multiple different machines.
Initially, it was thought that such capabilities could be given to the machines by use of the aforementioned Telnet application. Telnet is the Transmission Control Protocol/Internet protocol (TCP/IP) standard network virtual terminal protocol that (a) is used for remote terminal connection service, and (b) allows a user at one site to interact with systems at other sites as if that user terminal were directly connected to computers at those other sites. M. Weik, Communications Standard Dictionary 475 (3rd ed. 1996). Unfortunately, when designers attempted to implement the Telnet application to allow the newer machines to interact with the AS/400s, they found that standard Telnet was not adequate to the job.
As has been stated, many larger, older computer systems, such as the AS/400, antedated the WWW/Internet revolution. In addition, such systems also antedated the open systems revolution that also went hand-in-hand with the WWW/Internet revolution. Consequently, although the AS/400 had a great deal of flexibility and networking capability built into it, much of the software written for the AS/400 has been designed for and keyed to the actual physical hardware of the AS/400 (because the software designers failed to keep up with the capability of the machine), rather than being designed for and keyed to conceptual network communication layers as is done in modern times.
It was found by designers, when they tried to implement Telnet with older computers such as the AS/400, that in some instances much of the (often custom produced, and hence very expensive) software was actually keyed to and dependent upon the actual hardware of the terminals and/or the attendant connectors and busses associated with the terminals. In AS/400 systems, terminals are identified by actual, physical, switches and connections associated with three things: a specific I/O processor, a specific port number on the specific I/O processor, and a station number (#0-#6) on the specific port number. It is easy for an AS/400 system administrator to change the default device name (based on I/O processor, port, station) instead to some administrator selected name. This name stays with the terminal, at this address (I/O processor, port, station) until the name is changed. The name stays the same no matter who logs on to the terminal. Another way of stating the foregoing is that the older software was keyed to a particular device name.
One specific example of such a situation is an accounting program designed such that payroll data applications can only be run from a one specific physical terminal (in a locked room) identified by its specific physical identification parameters. Another specific example is a factory control program where certain applications programs are only available to certain specific terminals, identified by specific physical identification parameters, located throughout the factory. Yet another specific example is that where the language of operating systems instructions as displayed on a login terminal (e.g., German, or French) is determined by the specific location of a terminal, as identified by its specific physical identification parameters.
Business concerns have invested a great deal of money and time into their installed software bases, and are loath to discard such. Consequently, they desire that any replacement of existing physical terminals be compatible with the business concerns' preexisting software bases. Restated, business concerns do not want to be told that replacement of physical terminals, attached to their older computing systems, with virtual terminals will require that much preexisting software be discarded or rewritten due to the incompatibility of the older installed software with the newer virtual terminals.
Unfortunately, Telnet is not designed to be indicative of physical terminal characteristics (that is, Telnet does not allow a user to choose and thereafter utilize a particular device name); rather, it is designed only to support virtual terminal sessions (that is, Telnet was designed to allow remote logon, and was not designed with terminal replacement in mind), and is consequently incapable of designating any physical terminal characteristics (i.e., is incapable of supporting device names). Thus, it is apparent from the foregoing that a method and system that will allow the creation and utilization of virtual terminal sessions such that each virtual terminal may have associated with it a specific device name if application software is dependent upon such specific terminal identification number.